Method of fabricating a photographic aperture regulating device



P 1965 H. NERWIN ETAL 3,205,569

METHOD OF FABRICATING A PHOTOGRAPHIG APERTURE REGULATING DEVICE FiledJan. 10, 1964 2 Sheets-Sheet 2 Z Z 43 /2 FIG 4 44 45 27 KY r F IG. 7 24WARREN F ERR/S L/GHT HUBERT NERW/N SENS/N6 INVENTOR5 C/RCU/T BY fim/wATTORNEY United States Patent 3,205,569 METHOD OF FABRICATIN G APHOTOGRAPHIC APERTURE REGULATING DEVICE Hubert Nerwin and Warren Ferris,Rochester, N.Y., as-

signors to Eastman Kodak Company, Rochester, N.Y.,

a corporation of New Jersey Filed Jan. 10, 1964, Ser. No. 337,031 3Claims. (Cl. 29-407) This invention relates to a device for regulatingthe effective size of a photographic aperture, and more particularly toan adjustable. diaphragm vane device and method of making such a vanedevice that is positionable in accordance with interaction betweenpermanent magnet means and solenoid means variably energized as afunction of sensed illumination.

It is an object of this invention to regulate the effective size of aphotographic aperture by means of a simple device that iselectromagnetically positionable.

Another object of the invention is to reduce the manufacturing costs ofa photographic aperture regulating device.

Another object of the invention is to form a diaphragm vane means from asingle piece of material.

Another object of the invention is to eliminate the effects ofhysteresis on an electromagnetic diaphragm vane adjusting mechanism.

Another object of the invention is to position a diaphragm vane by meansof an electromagnetic actuator that is non-linear in its response tosensed illumination.

Another object of the invention is to regulate the effective size of adiaphragm aperture by means of a device that is reliable and accurate inoperation, and to make such a device by a method that is simple andeconomical.

Another object of the invention is to eliminate the multiplicity ofparts and reduce the relative movements of parts forming a diaphragmaperture size adjusting device.

These and other objects of the invention are accomplished by formingfrom a piece of bendable material an elongated member havinglongitudinally spaced notched vanes arranged so that when the member isbent into a U-shape, the notched vanes overlap and form an adjustableaperture the effective size of which varies as a function of the overlapof the vanes. Such a U-shaped or equivalent diaphragm vane device ispositioned by the magnetic repulsion between solenoid or coil meansvariably energized as a function of sensed illumination and permanentmagnet means, no other magnetic material being present within theeffective magnetic field of the solenoid means. will be more clearlyunderstood by reference to the following description and theaccompanying drawings wherein:

FIGS. 1 and 2 show partially schematic, partially sectioned front planviews of a diaphragm aperture adjusting device according to theinvention.

FIG. 3 shows a partially schematic, partially sectioned side view of thedevice of FIGS. 1 and 2.

FIGS. 4 and 5 show steps in the method of fabricating the diaphragm vaneillustrated in FIGS. 1-3.

FIG. 6 shows a plan view of an alternate vane configuration suitable fora single piece diaphragm vane device.

FIG. 7 shows a partially schematic, partially sectioned front plan viewof a two-vane diaphragm aperture and adjusting device accroding to theinvention.

As shown in FIGS. 1-3, a U-shaped diaphragm vane member 10 has legportions 11 and 12 integral with vanes 13 and 14 that have respectivenotches 15 and 16 for regulating the effective size of photographicaperture 17 as a function of the overlap of the vanes. The overlap Theinvention of the vanes 13 and 14 is in turn regulated by the position ofleg portions 11 and 12 of U-shaped member 10. U-shaped member 10 issupported in a holder 18 having an adjusting screw 19 for calibratingthe overlaps of vanes 13 and 14.

To incorporate the aperture adjusting member 10 into a photographiccamera, holder 18 is fixed to the camera so as to position notches 15and 16 over a camera taking lens aperture 17 for varying its effectivesize. To facilitate such an arrangement, camera taking lenses 20-22 canbe associated with aperture 17 as shown in FIG. 3.

For positioning vanes 13 and 14 so as to regulate the effective size ofaperture 17, a coil or solenoid 23 is in circuit with schematicallyillustrated light-sensing circuit 24 so that solenoid 23 is variablyenergized as a function of sensed illumination. Many well-knownphotocell circuits including unassisted selenium cells, photoconductivecells with batteries, and amplified photocell outputs may be used aslight-sensing circuit 24. Typically such photocells are arranged foraccepting illumination from a scene to be photographed.

Interacting with the variable field of solenoid 23 are two peramentmagnets 25 and 26 fixed respectively to arms 27 and 28 so as to extendinto the hollow center of solenoid 23 as shown in FIG. 1 whereversolenoid 23 is unenergized. Diaphragm adjusting member 10 including legs11 and 12 and arms 27 and 28 is preferably formed of nonmagneticmaterial so as not to be affected by the magnetic field of solenoid 23.Magnetic material within the effective variable field of solenoid 23such as soft iron that is subject to the effects of hystersis wouldintroduce inaccuracies into the functioning of diaphragm aperture vanes13 and 14. In other Words, such magnetic material would retain someresidual magnetism after a cycle of operation of coil 23 depending onprevious induced magnetism and thus would start each aperture regulatingcycle with variable and unknown conditions of induced magnetism. Thisresults in inaccuracies in the positioning of vanes in response to theenergization of coil 23. By eliminating from the effective magneticfield of solenoid 23 all magnetic material other than permanent magnets25 and 26, the errors produced by hysteresis are eliminated. Permanentmagnets 25 and 26 retain their fixed values of induced magnetism so asnot to be subject to any variation from hysteresis effect. Once theinaccuracies from variable magnetic reactions from hysteresis areeliminated, a simple device such as illustrated in FIGS. l-3 canfunction accurately to regulate the effective size of aperture 17 as afunction of the illumination sensed by light-sensing circuit 24.

The interaction between the variable magnetic field of solenoid 23 andpermanent magnets 25 and 26 is one of magnetic repulsion. This has theadvantage of positioning vanes 13 and 14, as a function of a non-linearresponse to sensed illumination. Since the magnetic field strengthwithin the hollow core of solenoid 23 for any given value ofenergizati-on is uniform from the center to the edges of the coil, andis strongest throughout such a zone, magnets 25 and 26 react to thegreatest repulsive forces available for the lower values of illuminationand to relatively decreased repulsive forces for increases inillumination from higher values of light intensity. Thus, when sensedillumination is at low values, magnets 25 and 26 are relatively stronglyrepulsed toward the ends of coil 23 and for intense illumination andrelatively high energization levels of solenoid 23, magnets 25 and 26begin to withdraw from the ends of coil 23 and increased illuminationproduces relatively weaker increases in repulsive forces. This isdesirable for approximating the log-linear conversion of sensed lightintensity to mechanical movement.

Of course, the relative positions of solenoid and permanent magnetscould be interchanged. Thus, two hollow solenoids could move over theends of a fixed permanent magnet. Also, solenoid 23 could be formed intwo connected coils and arms 27 and 28 could be located in anotherposition, for example, bent outwardly of legs 11 and 12 for interactingwith separate solenoid coils. Alternatively, the solenoid could be fixedto one leg of member and a permanent magnet fixed to the other leg.

In FIG. 7 is illustrated an alternative embodiment of the inventionusing two pivoted diaphragm vanes 30 and 31 having respective falcate orsickle-shaped openings 32 and 33 co-operating to define photographicaperture 17 that is variable as a function of the overlap of vanes 30and 31. Vanes 30 and 31 are mounted for rotation about pivot points 34and 35 respectively. Respective springs 36 and 37 operate to returnvanes 30 and 31 from any deflected position to the position illustratedin FIG. 7 in which vane openings 32 and 33 provide maximum effectivesize for aperture 17. Permanent magnets 25 and 26, fixed respectively tovanes- 30 and 31, interact repulsively with coil 23, and light sensingcircuit 24 variably energizes coil 23both as described above for FIGS.1-3.

One advantage of the diaphragm aperture adjusting member 10 illustratedin FIGS. 1-3 is that it can be manufactured from a single piece ofmaterial by an advantageous method, steps of which are illustrated inFIGS. 4-6. A piece of bendable and preferably non-magnetic materialshould be selected, suitable materials including non-magnetic metalssuch as aluminum and various plastics. To make the diaphragm vane member10 illustrated in FIGS. 1-3, the elongated member 10 illustrated in FIG.4 is cut from a flat piece of bendable material. Such member has legportions 11 and 12 and vanes 13 and 14 having respective notches 15 and16. Arms 27 and 28 also extend from leg portions 12 and 11 respectively.Although arms 27 and 28, and vanes 13 and 14 may extend from either oralternate sides of member 10, it is preferred that vanes 13 and 14extend from the same lateral side of elongated member 10 as illustratedin FIG. 4.

Alternatively, vane 40 having notch 41 as illustrated in FIG. 6 may besubstituted for the vane configuration of vanes 13 and 14 as illustratedin FIGS. 4 and 5.

Right angle bends are formed at dotted lines 42-45 or 46 that arelocated Where vanes and arms project laterally from elongated member 10.Such right angle bends are made so that vanes 13 and 14 extend from thesame face of leg portions 12 and 11 respectively as illustrated in FIG.5. In such position vanes 13 and 14 are coplanar in a plane normal tothe plane of leg portions 11 and 12. Arms 27 and 28 are similarly bentat right angles so as to project from the same face of leg portions 11and 12, but, as indicated above, arms 27 and 28 could be bent inopposite right angles so that either one or both of arms 27 and 28extended in a direction 180 rotational degrees from the directionillustrated in FIG. 5. The determining factor for the bends of arms 27and 28 is the desired location and number of solenoids or permanentmagnets.

When the member, 10 formed as illustrated in FIG. 5, is bent into aU-shape as illustrated in FIGS. l-3, vanes 13 and 14 overlap to definethe effective size of aperture 17. With the fixing of permanent magnets25 and 26 to 4 arms 27 and 28 respectively, diaphragm aperture adjustingmember 10 is ready for insertion into holder 18. Adjustment of screw 19calibrates member 10 for operation.

The advantages of the above-described vane manufacturing method includesimplicity, economy of parts, elimination of assembly operations, andreduction of the possibilities for manufacturing errors, all of whichcontribute to economy of manufacture.

The invention has been described in detail with particular reference topreferred embodiments thereof but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim.

1. A method of fabricating a photographic aperture regulating device,comprising:

(a) from a fiat piece of bendable material, forming and elongated striphaving a pair of longitudinally spaced, notched vanes extendinglaterally from one side of said strip adjacent the opposite endsthereof;

(b) forming an approximately right angle blend where each of said vanesjoins said elongated strip so that said vanes extend in the same generaldirection from said elongated strip and are approximately coplanar in aplane normal to the plane of said elongated strip; and

(c) bending said elongated strip into a U-shape so that said vanesartially overlap and their respective notches cooperate to define anaperture that is variable in size as a function of the overlap of saidvanes.

2. A method of fabricating a photographic aperture regulating device,comprising:

(a) cutting from a flat piece of bendable material an elongated striphaving near its opposite ends a air of notched vanes extending laterallyfrom the same side of said strip, and having two tabs extendinglaterally from one side of said strip at locations therealong spacedfrom one another and from said vanes;

(b) forming approximately right angle bends Where each of said vanesjoins said elongated strip so that said vanes extend in the same generaldirection from said elongated strip and are approximately coplanar in aplane normal to the plane of said elongated strip;

(c) similarly forming approximately right angle bends where each of saidtabs joins said elongated strip so that said tabs also extend in acommon direction from said strip; and

(d) bending said elongated strip into a U-shape o that said tabs are ingeneral alignment with one another and said vanes partially overlap andtheir respective notches cooperate to define an aperture that isvariable in size as a function of the overlap of said vanes.

3. The method of claim 2 with the additional step of fixing permanentmagnets to said tabs.

References Cited by the Examiner UNITED STATES PATENTS 2,754,580 7/56Schlaich 29551 3,082,674 3/63 Bagby. 3,104,455 9/63 Frost 29l55.6

WHITMORE A. WILTZ, Primary Examiner.

THOMAS H. EAGER, Examiner.

1. A METHOD OF FABRICATING A PHOTOGRAPHIC APERTURE REGULATING DEVICE,COMPRISING: (A) FROM A FLAT PIECE OF BENDABLE MATERIAL, FORMING ANDELONGATED STRIP HAVING A PAIR OF LONGITUDINALLY SPACED, NOTCHED VANESEXTENDING LATERALLY FROM ONE SIDE OF SAID STRIP ADJACENT THE OPPOSITEENDS THEREOF, (B) FORMING AN APPROXIMATELY RIGHT ANGLE BLEND WHERE EACHOF SAID VANES JOINS SAID ELONGATED STRIP SO THAT SAID VANES EXTEND INTHE SAME GENERAL DIRECTION FROM SAID ELONGATED STRIP AND AREAPPROXIMATELY COPLANAR, IN A PLANE NORMAL TO THE PLANE OF SAID ELONGATEDSTRIP; AND (C) BENDING SAID ELONGATED STRIP INTO A U-SHAPED SO THAT SAIDVANES PARTIALLY OVERLAP AND THEOR RESPECTIVE NOTCHES COOPERATE TO DEFINEAN APERTURE THAT IS VARIABLE IN SIZE AS A FUNCTION OF THE OVERLAP OFSAID VANES.